In related art, a projector including a light source, alight modulation device that modulates light output from the light source according to image information, and a projection optical device that projects the light modulated by the light modulation device is known. The projection optical device has a plurality of lens groups. Further, of the plurality of lens groups, a projection lens (projection optical device) having the lens group adapted to be movable along an optical axis and a projector including the projection lens are disclosed (for example, see PTL 1).
The projection lens described in PTL 1 includes first to fifth lens groups, a focus tube that holds the first lens group, three lens frames that respectively hold the second to fourth lens groups, a guide tube, a cam tube, and a fixed frame that supports the guide tube. Each lens frame has a cam pin that engages with a rectilinear groove of the guide tube and a cam groove of the cam tube and is inserted into the guide tube. The fifth lens group is held by the fixed frame.
Then, when the focus tube is rotated, the first lens group moves and focus adjustment is made, and, when the cam tube is rotated, the second to fourth lens groups move and zoom adjustment is made.